Perforating continuous pavement cutter

ABSTRACT

An apparatus used in conjunction with the ripper bar of a prime mover for perforating a section of overlaying asphaltic pavement along a cutting line, which consists of a ground engaging wheel formed with a toothed cutting edge, and a blade for lifting a severed portion of pavement into engagement with the cutting edge so as to be sheared along a well defined cutting line.

United States Patent [191 Soderlund Nov. 20, 1973 PERFORATING CONTINUOUS PAVEMENT CUTTER [761 Inventor: Vernon R. Soderiund, 6514 A Lucas Ave., Oakland, Calif. 94611 [22] Filed: Aug. 10, 1972 [21] Appl. No.: 279,345

[52] US. Cl. 299/40, 299/86 [51] Int. Cl. E0lc 23/09 [58] Field of Search 299l3 6 4l [56] References Cited UNITED STATES PATENTS 12/1969 Soderlund 299/36 Pedrick 299/39 Laster 299/39 Primary Examiner-Emest R. Purser Attorney-James R. Cypher [57] I ABSTRACT An apparatus used in conjunction with the ripper bar of a prime mover for perforating a section of overlaying asphaltic pavement along a cutting line, which consists of a ground engaging wheel formed with a toothed cutting edge, and a blade for lifting a severed portion of pavement into engagement with the cutting edge so as to be sheared along a well defined cutting line.

7 Claims, 4 Drawing Figures PERFORATING CONTINUOUS PAVEMENT CUTTER BACKGROUND OF THE INVENTION This invention is an improvement of my Continuous Pavement Cutter described in U. S. Pat. No. 3,592,509, granted July 13, 1971. In the use of the foregoing cutter it was observed that relatively large and powerful prime movers were needed to pull the cutter at a continuous rate. Even the larger tractors had difficulty in maintaining a straight line when the pavement to be cut was relatively thick. Further, the smooth ground engaging wheel of the former cutter had a tendency to skid rather than roll along the pavement which increased the drag of the device.

SUMMARY OF THE INVENTION The gist of the present invention is an annular toothed cutter ring mounted on the ground engaging wheel on the cutting line. This toothed wheel not only aids in cutting the pavement but reduces to some extent the drag of the device because the teeth reduce the tendency for the wheel to akid along the pavement.

An object of the cutting ring is to increase the cutting efficiency of the apparatus so that the power requirements of the prime mover may be reduced.

A further object is to provide a cutter as described which is capable of making cleaner and straighter cuts in asphaltic concrete pavements.

A still further feature is to provide a reference point which will enable prime mover operators to more closely hew to the designated cutting line.

Still another object is to provide a device which can be made lighter and will last longer than previous cutters.

A further object is to provide a ground engaging wheel which will not skid but will continue rolling during forward movement of the device.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of the device constructed in accordance with the present invention.

FIG. 2 is a rear view of the device shown in FIG. 1 with portions in section and other portions shown in dashed line to show their relationship to other parts of the device.

FIG. 3 is a cross section of a portion of the device taken along line 3-3 of FIG. 1.

FIG. 4 is a cross section of the device taken along line 44 of FIG. 1.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The improved cutter of the present invention consists briefly of a frame 1 adapted for attachment to a prime mover 2; a pavement engaging wheel 3 rotatably mounted on the frame adapted for applying surface pressure against the pavement 4 over a substantially sufficient area to prevent pavement uplift beneath the 3 wheel and laterally away from the blade set forth below; annular cutting means 6 mounted on one edge '7 of the wheel extending radially outwardly from the surface of the wheel adapted for making a shallow perforated cut 8 in the pavement on a cutting line 9; and a blade II mounted on the frame spaced laterally away from the ground wheel and having a forward elongated edge 12 positioned at a lower elevation relative to the ground wheel for slicing a thickness of pavement from the subgrade 13, a first side 14 of the forward edge being substantially in alignment with the annular cutting means 6, the blade extending rearwardly and upwardly from the leading edge adapted to lift a continuous sheet portion 16 of pavement against the annular cutting means causing a shearing of the pavement along the cutting line 9.

In the preferred embodiment, the annular cutting means includes a plurality of teeth 17 extending radially outwardly from the wheel and adapted for making shallow perforations in the pavement along the cutting line 9. The perforations are as deep as the length of the cutting teeth. The length of the teeth may vary between approximately the root width and twice the root width of the teeth. In order to increase the efiiciency of cutting the perforations, the teeth, as viewed in side elevation may have a root width w greater than a tip width w. Another way to improve the efficiency is to form the teeth, as viewed in cross section with a root thickness t greater than a tip thickness t, In practice, I have found that tapering the teeth in both the width and thickness is the most efficient tooth structure. Thus the actual tip area 18 of each of the teeth is relatively small as compared with the root area of the tooth.

Another feature of the present invention is the use of a wheel formed with a continuously decreasing diameter with the ground engaging surface 4 tapering upwardly from the annular cutting means so that the wheel is adapted for applying greater pressure against the pavement immediately adjacent the cutting line 9. Thus, the diameter of the wheel at circumference line 19 is greater than the diameter of the wheel at its outer edge at circumference line 21.

FIGS. 3 and 4 are sections through a special replaceable cutting shoe 22 which is attached to the frame. It was found that a cleaner cut resulted when a raised portion 23 in relation to the rest of the blade 24 was formed in the replaceable shoe such as a full shoe arrangement with sides 26 and 27 and base 30. The replaceable shoe slips over a foot 28 on the frame so that the undersurface 29 of the replaceable cutting shoe fits in close fitting relation with an upper surface 31 of the foot.

The frame of the device includes a shank portion 33 which is attached to a ripper bar 34 of a prime mover such as a crawler tractor, wheeled loader or grader by means of a pin 36 or other means. The shank preferably includes a C-shaped portion 37 which curves rearwardly from the shank and then curves forwardly; terminating in the foot 28. The wheel is mounted on an axle 38 which is journaled in a bore 39 in the frame. The axle is formed with threaded ends 41 and 42 which receive locking nuts 47 and 48 respectively. The axle is formed with a flange 38. The wheel is held on the axle by steel thrust rings 44 and bronze washers 43 and 43'. Bronze bushings 46 and 46' are pressed firmly into the bore of the wheel for free rotation of the cutting wheel. A ring 38 is placed between the wheel and the flange. A steel thrust ring 45 is placed between the lock nut 48 and the frame.

Operation of the pavement cutter is similar to my cutter described in the above named patent. The cutting edge 12 is set to ride at approximately the subgrade level just below the thickness of the pavement. The operator lowers his ripper bar so that the adge 12 cuts into the pavement and continues downwardly until the teeth 17 have sunk into the pavement and the wheel surface rests on the pavement. As the tractor moves forwardly, the edge 12 severs the pavement from the subgrade and a portion of the pavement is lifted upwardly as it rides up on the shoe. As the pavement moves upwardly, it breaks along the cutting line 9 with the aid of the prior perforations made by the teeth and due to the shearing action. Only portion 52 of the pavement can continue rising as the pavement under the wheel is held immobile by the weight of the wheel. The bending of the pavement causes tension cracks 53 at the base of the pvavement and compression buckling failure lines 54 at the top of the pavement. While a portion of the pavement is broken up, a relatively straight edge 56 is left along the cutting line 9.

One of the unexpected results of adding teeth to the ground engaging wheel was the fact that it took less power to pull the device than a device without the teeth. Part of this efficiency is due to the perforations which permit easier shearing of the pavement but part of the efficiency results from the fact that the ground engaging wheel with the teeth skids very little during forward movement. Thus, rolling friction has replaced the skidding friction of the wheel and it is much less. In viewing the operation of the device, it is apparent that only a small fraction of the weight of the tractor is needed to hold the ground engaging wheel on the pavement to prevent uplift. Most of the weight is needed to obtain traction of the metal crawler treads on the smooth pavement. it is to be understood that most tractors which work on urban streets are not fitted with lugs in order to do as little damage to the pavement as possible.

It was found that it was not necessary to space the teeth closely together. For example, on an 8 inch diameter wheel with teeth having a length of about 1 /1 inches to l inches only about nine teeth are required. This means that the spacing s between teeth may be greater than the width w of the individual teeth.

I claim:

1. A pavement cutter comprising:

a. a frame adapted for attachment to a prime mover;

b. a pavement engagement wheel rotatably mounted on said frame adapted for applying surface pressure against the pavement over a substantially sufficient area to prevent pavement uplift beneath said wheel and laterally away from the blade set forth below;

c. annular cutting means mounted on one edge of said wheel extending radially outwardly from the surface of said wheel adapted for making a shallow cut in said frame spaced on a cutting line;

d. a blade mounted on said frame spaced laterally away from said ground wheel and having a forward elongated edge positioned at a lower elevation relative to said ground wheel for slicing a thickness of pavement from the subgrade, a first side of said forward edge being substantially in alignment with said annular cutting means, said blade extending rearwardly and upwardly from said leading edge adapted to lift a continuous sheet of pavement against said annular cutting means causing a shearing of said pavement along said cutting line; and

e. said annular cutting means including a plurality of teeth extending radially outwardly from said wheel and adapted for making shallow perforations in said pavement along said cutting line.

2. A pavement cutter as described in claim 1 comprising:

a. said wheel being formed with a continuously decreasing diameter with the ground engaging surface tapering upwardly from said annular cutting means so that said wheel is adapted for applying greater pressure against the pavement immediately adjacent said cutting line.

3. A pavement cutter as described in claim 1 comprising:

a. said teeth, as viewed in side elevation having a root width greater than a tip width.

4. A pavement cutter as described in claim 1 comprising:

a. said teeth, as viewed in cross section having a root thickness greater than a tip thickness.

5. A pavement cutter as described in claim 4 comprising:

a. said teeth as viewed in side elevation having a root width greater than a trip width.

6. A pavement cutter as described in claim 1 comprising:

a. said blade adjacent said first side and rearwardly of said forward edge rising more rapidly from front to rear than the other side adapted to raise said lifting pavement along said cutting line higher than at any other point on said pavement.

7. A pavement cutter as described in claim 1 comprising:

a. the spacing of each of said teeth along the circumference of said wheel being greater than the distance between each of said teeth. 

1. A pavement cutter comprising: a. a frame adapted for attachment to a prime mover; b. a pavement engagement wheel rotatably mounted on said frame adapted for applying surface pressure against the pavement over a substantially sufficient area to prevent pavement uplift beneath said wheel and laterally away from the blade set forth below; c. annular cutting means mounted on one edge of said wheel extending radially outwardly from the surface of said wheel adapted for making a shallow cut in said frame spaced on a cutting line; d. a blade mounted on said frame spaced laterally away from said ground wheel and having a forward elongated edge positioned at a lower elevation relative to said ground wheel for slicing a thickness of pavement from the subgrade, a first side of said forward edge being substantially in alignment with said annular cutting means, said blade extending rearwardly and upwardly from said leading edge adapted to lift a continuous sheet of pavement against said annular cutting means causing a shearing of said pavement along said cutting line; and e. said annular cutting means including a plurality of teeth extending radially outwardly from said wheel and adapted for making shallow perforations in said pavement along said cutting line.
 2. A pavement cutter as described in claim 1 comprising: a. said wheel being formed with a continuously decreasing diameter with the ground engaging surface tapering upwardly from said annular cutting means so that said wheel is adapted for applying greater pressure against the pavement immediately adjacent said cutting line.
 3. A pavement cutter as described in claim 1 comprising: a. said teeth, as viewed in side elevation having a root width greater than a tip width.
 4. A pavement cutter as described in claim 1 comprising: a. said teeth, as viewed in cross section having a root thickness greater than a tip thickness.
 5. A pavement cutter as described in claim 4 comprising: a. said teeth as viewed in side elevation having a root width greater than a trip width.
 6. A pavement cutter as described in claim 1 comprising: a. said blade adjacent said first side and rearwardly of said forward edge rising more rapidly from front to rear than the other side adapted to raise said lifting pavement along said cutting line higher than at any other point on said pavement.
 7. A pavement cutter as described in claim 1 comprising: a. the spacing of each of said teeth along the circumference of said wheel being greater than the distance between each of Said teeth. 